This invention relates to hot melt ink supply systems for supplying hot melt ink to an ink jet apparatus and, more particularly, to a new and improved hot melt ink supply system which can be used to supply hot melt pigmented ink.
In hot melt ink jet systems, the ink is delivered to the ink jet apparatus in solid form and must be melted and kept in a molten condition for immediate use by the ink jet head. Normally, this requires the complete ink supply system to be kept at a temperture such as 120.degree. C. at which the ink is maintained in a molten condition, requiring substantial expenditure of energy. Moreover, if the hot melt ink in the apparatus contains an insoluble pigment rather than a soluble dye, the ink must be stirred as long as it is molten in order to avoid undesirable settling of the pigment. Conventional hot melt ink supply systems are generally incapable of avoiding settling of pigment in a pigmented hot melt ink.
Accordingly, it is an object of the present invention to provide a new and improved hot melt ink supply system which overcomes the above-mentioned disadvantages of the prior art.
Another object of the invention is to provide an improved hot melt ink supply system for ink jet apparatus which is especially adapted for use with pigmented hot melt inks.
A further object of the invention is to provide a hot melt ink supply system which is arranged to avoid undesirable settling of pigment from a hot melt ink with minimum energy expenditure.